1. Field of the Invention
This invention relates to improvements in an electronic key apparatus for vehicle for verifying an ID code by communication between a vehicle mounted device and a portable device for vehicle and locking and unlocking a door, a handle lock, a box or a trunk and starting an engine, etc.
2. Description of the Related Art
Conventionally, in the case of starting an engine or locking and unlocking a door of a vehicle, there were means in which a user inserts a key into a keyhole and rotates the key, or an electronic key apparatus such as the so-called card key in which wireless communication between a vehicle mounted device and a key (a portable device) is conducted without touching the key at all with the key put in a bag or a pocket of a user and an ID code from the portable device is verified against a code stored in the vehicle mounted device and when the ID code matches with the code, a vehicle mounted control device can lock or unlock the door.
Also, in the electronic key apparatus as described above, an ID of the portable device must be previously registered in the vehicle mounted device and its registration method was a method in which after setting in a registration mode by a predetermined procedure using the existing switch, the vehicle mounted device receives a code from the portable device and registers the code.
The Japanese Patent No. 3,589,188 was means in which in communication between a portable device and a vehicle mounted device, for prevention of leaving the portable device in a vehicle room, wireless communication from the vehicle mounted device to the portable device is conducted and when the portable device makes no response, it is recognized that the portable device is not present in the vehicle room. Also, the Japanese Patent No. 3,191,607 was means in which it is necessary to newly register a code of a portable device in a vehicle mounted device because of loss etc. of the portable device and the code can be registered by a simple method. In the case of a conventional mechanical key, some users hid the key in a certain place of a vehicle in consideration of loss or leaving of possession. In case of an emergency, use was made by taking this key out of the hidden place and starting an engine of the vehicle in order to save the day. However, in the case of a type of key for communicating with a vehicle mounted device by a portable device such as a card key, there is a problem that the card key cannot be used as a spare key similar to the mechanical key simply.
Generally, a vehicle is delivered to a user with the vehicle preset so as to be able to cope with plural portable devices. For example, it is assumed that three portable devices of A, B and C are registered and the vehicle is delivered. When the user attempts to drive the vehicle using the portable device of A among them, a series of actions in which a vehicle mounted device issues a request signal for requesting an ID code for verification and when the portable device receives this signal, an ID code corresponding to the request signal is returned as an answer signal are performed. In this case, the actions are performed in the portable device using a built-in battery as a power source generally. Also, the vehicle mounted device does not know which portable device among the three portable devices the user uses, so that the vehicle mounted device issues the request signal to all the available portable devices of A, B and C. Here, when the portable device C is arranged as a spare in a predetermined place of the vehicle and in the range in which the request signal reaches, the portable device makes a response and there are fears that a battery is rapidly consumed wastefully and also, for example, it is decided that the portable device is arranged inside a vehicle room.